Bourbon
American whiskey made from a grain mash of at least 51% corn, aged in new charred oak — defined by US federal law.
Bourbon is an American whiskey defined by the US Federal Standards of Identity for Distilled Spirits (27 CFR Part 5). The legal requirements: produced in the United States; made from a grain mash containing at least 51% corn; distilled at no more than 160 proof (80% ABV); stored in charred new oak containers; entered into the barrel at no more than 125 proof (62.5% ABV); bottled at no less than 80 proof (40% ABV). Kentucky accounts for approximately 95% of bourbon production by volume, though bourbon may legally be produced in any US state.
Quick facts
- Type
- Style
- Style
- bourbon
- Mash bill
- ≥ 51% corn
- Minimum aging
- No minimum (straight bourbon ≥ 2 years)
- Origin
- United States
Federal Standards of Identity
27 CFR 5.22(b)(1) defines bourbon: produced in the US, ≥ 51% corn in the mash bill, distilled to ≤ 80% ABV, entered into new charred oak at ≤ 62.5% ABV, bottled at ≥ 40% ABV. 'Straight bourbon' requires at least two years of maturation and prohibits added colouring or flavouring. 'Kentucky Straight Bourbon' must be produced in Kentucky. The new-charred-oak requirement is the defining technical constraint and the primary source of flavour.
Mash Bill Variations
Typical bourbon mash bills range from 65–80% corn with 10–20% malted barley (to provide starch-converting enzymes) and 5–15% rye or wheat. 'Wheated bourbon' substitutes wheat for rye, producing a softer, sweeter character (Maker's Mark, W.L. Weller, Pappy Van Winkle). High-rye bourbons (Bulleit, Four Roses high-rye recipes) emphasise spice and dryness.
Sources & further reading (1)
- encyclopedia — accessed 2026-05-15
Frequently asked questions
Does bourbon have to be made in Kentucky?
No. US federal law requires only that bourbon be produced in the United States. Bourbon is made in Texas, Colorado, New York, and many other states. Kentucky accounts for roughly 95% of production by volume because its climate and limestone water are well suited to the spirit, but 'Kentucky' is a geographic designation under separate state law.
How long must bourbon be aged?
There is no minimum age for bourbon to be labelled 'bourbon' — only for it to be labelled 'straight bourbon' (two years) or to carry an age statement (which must reflect the youngest spirit in the bottle). Bourbon aged less than four years must carry an age statement on the label.